Peat layers and Arctic forests may insulate permafrost from rising air temperatures
Permafrost, a layer of soil or rock that remains at or below 0 °C for two or more years, may be buffered against the impacts of climate change by certain types of soil and vegetation1. Melting permafrost has been implicated in damage to Arctic and sub-Arctic infrastructure, and as a possible source of methane, a greenhouse gas.
Shuhua Yi and colleagues at McMaster University, Ontario, used the Community Land Model Version 3 and historical climate records to simulate the depth of summer ground thaw at two sites in the Northwest Territories of Canada under a scenario of future warming. Although permafrost degradation was predicted for all sites in the 2000 to 2100 period, areas with mineral-based soil and no vegetation were most affected. Forest cover provided more protection than shrubs or bare ground, and thick layers of peat-rich soil were such effective insulators that permafrost showed only minimal decline even by 2100.
Previous studies suggest that rising temperatures over the coming century would melt up to 90% of Northern Hemisphere permafrost, but these new results suggest the permafrost response will not be uniform. Extensive land management, including the preservation of forested and peat-rich areas, may be the key to maintaining permafrost into the future.
Yi, S., Woo, M. & Arain, M.A. Impacts of peat and vegetation on permafrost degradation under climate warming, Geophys. Res. Lett. 34, doi:10.1029/2007GL030550 (2007).